As Gene Tests Spread, Questions Follow

By

Gautam Naik

Updated Dec. 13, 2007 11:59 p.m. ET

Ever since the human genome was deciphered seven years ago, companies have been rushing to sell genetic tests directly to consumers. But buyers, beware: Many of the claims that accompany these tests are not fully supported by science.

Some 1,400 genetic tests are currently available. There are tests that aim to identify the gender of a fetus as early as seven weeks after conception. Some companies test for traits such as a "sweet tooth gene," and then sell tailored supplements to hasten weight loss. And there are...